Stem cells have tremendous potential in regenerative medicine applications. The generation of induced pluripotent stem cells (iPSCs) bypasses the ethical and immune rejection issues of human embryonic stem cells (hESCs), and provides an unlimited cell source for tissue repair. However, the differentiation and the therapeutic effects of iPSC-derived stem cells have not been well characterized in vitro and in vivo. Here we propose to investigate the differentiation and therapeutic effects of iPSC- derived neural crest stem cells (NCSCs). NCSCs can be derived from ESCs and iPSCs, and can generate many cell types (neural cells, vascular cells, mesenchymal cells, endocrine cells) of all three germ layers, which make it a valuable stem cell source and an ideal model system to study the lineage commitment and therapeutic potential of multipotent stem cells. In addition, nanofibrous biomaterials will be used as scaffolds to deliver stem cells and provide a well-controlled and tissue-specific microenvironment for the investigations of NCSC differentiation and tissue regeneration in vivo. We hypothesize that iPSC-derived NCSC is a valuable cell source for the regeneration of neural, vascular and other tissues and that the differentiation of NCSCs in vivo depends on tissue-specific microenvironment. To test our hypothesis, three Specific Aims are proposed: (1) To derive and characterize NCSCs from iPSCs and ESCs and investigate their differentiation in vitro, (2) To determine the differentiation and therapeutic potential of NCSCs in nanofibrous nerve conduit for peripheral nerve regeneration in vivo, and (3) To determine the differentiation and therapeutic potential of NCSCs in nanofibrous vascular grafts for vascular regeneration in vivo. We will take a multidisciplinary approach and integrate the knowledge and technologies from stem cell biology, biomaterials, tissue engineering, nanotechnology and medicine. The accomplishment of this project will advance our understanding on the differentiation and therapeutic potential of iPSCs and NCSCs, and provide a rational basis for the use of iPSCs and NCSCs, in combination with nanofibrous scaffolds, in the regeneration of neural and vascular tissues. In addition, the research on iPSC-NCSCs will have impact on the therapies for many other diseases such as demyelinating disorders, congenital heart failure, spina bifida, arthritis, osteoporosis and endocrine disorders.